21204227 has 8 divisors (see below), whose sum is σ = 23477952. Its totient is φ = 18988200.

The previous prime is 21204223. The next prime is 21204241. The reversal of 21204227 is 72240212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21204227 - 2² = 21204223 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21204199 and 21204208.

It is not an unprimeable number, because it can be changed into a prime (21204223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13649 + ... + 15122.

It is an arithmetic number, because the mean of its divisors is an integer number (2934744).

Almost surely, 2^21204227 is an apocalyptic number.

21204227 is a deficient number, since it is larger than the sum of its proper divisors (2273725).

21204227 is a wasteful number, since it uses less digits than its factorization.

21204227 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28849.

The product of its (nonzero) digits is 448, while the sum is 20.

The square root of 21204227 is about 4604.8047732776. The cubic root of 21204227 is about 276.7838939683.

Adding to 21204227 its reverse (72240212), we get a palindrome (93444439).

The spelling of 21204227 in words is "twenty-one million, two hundred four thousand, two hundred twenty-seven".